class Person {
    // 方法重载
    void sayInfo() {
        System.out.println("some empty info");
    }

    void sayInfo(String name) {
        System.out.println("name is " + name);
    }

    void sayInfo(String name, int age) {
        System.out.println("name is " + name + ", age is " + age);
    }
}

public class Test {
    public static void main(String[] args) {
        Person p = new Person();
        p.sayInfo();
        p.sayInfo("Alice");
        p.sayInfo("Bob", 30);
    }
}